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80 lines
3.0 KiB
80 lines
3.0 KiB
commit 6ca53a2453598804a2559a548a08424fca96434a |
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Author: Florian Weimer <fweimer@redhat.com> |
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Date: Mon Jan 21 09:26:41 2019 +0100 |
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resolv: Do not send queries for non-host-names in nss_dns [BZ #24112] |
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Before this commit, nss_dns would send a query which did not contain a |
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host name as the query name (such as invalid\032name.example.com) and |
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then reject the answer in getanswer_r and gaih_getanswer_slice, using |
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a check based on res_hnok. With this commit, no query is sent, and a |
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host-not-found error is returned to NSS without network interaction. |
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diff --git a/resolv/nss_dns/dns-host.c b/resolv/nss_dns/dns-host.c |
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index 1e85e4f08ffc8600..e697d9103797341b 100644 |
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--- a/resolv/nss_dns/dns-host.c |
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+++ b/resolv/nss_dns/dns-host.c |
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@@ -273,11 +273,26 @@ gethostbyname3_context (struct resolv_context *ctx, |
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return status; |
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} |
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+/* Verify that the name looks like a host name. There is no point in |
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+ sending a query which will not produce a usable name in the |
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+ response. */ |
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+static enum nss_status |
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+check_name (const char *name, int *h_errnop) |
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+{ |
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+ if (res_hnok (name)) |
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+ return NSS_STATUS_SUCCESS; |
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+ *h_errnop = HOST_NOT_FOUND; |
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+ return NSS_STATUS_NOTFOUND; |
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+} |
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+ |
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enum nss_status |
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_nss_dns_gethostbyname2_r (const char *name, int af, struct hostent *result, |
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char *buffer, size_t buflen, int *errnop, |
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int *h_errnop) |
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{ |
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+ enum nss_status status = check_name (name, h_errnop); |
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+ if (status != NSS_STATUS_SUCCESS) |
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+ return status; |
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return _nss_dns_gethostbyname3_r (name, af, result, buffer, buflen, errnop, |
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h_errnop, NULL, NULL); |
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} |
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@@ -288,6 +303,9 @@ _nss_dns_gethostbyname_r (const char *name, struct hostent *result, |
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char *buffer, size_t buflen, int *errnop, |
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int *h_errnop) |
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{ |
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+ enum nss_status status = check_name (name, h_errnop); |
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+ if (status != NSS_STATUS_SUCCESS) |
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+ return status; |
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struct resolv_context *ctx = __resolv_context_get (); |
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if (ctx == NULL) |
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{ |
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@@ -295,7 +313,7 @@ _nss_dns_gethostbyname_r (const char *name, struct hostent *result, |
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*h_errnop = NETDB_INTERNAL; |
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return NSS_STATUS_UNAVAIL; |
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} |
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- enum nss_status status = NSS_STATUS_NOTFOUND; |
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+ status = NSS_STATUS_NOTFOUND; |
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if (res_use_inet6 ()) |
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status = gethostbyname3_context (ctx, name, AF_INET6, result, buffer, |
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buflen, errnop, h_errnop, NULL, NULL); |
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@@ -312,6 +330,9 @@ _nss_dns_gethostbyname4_r (const char *name, struct gaih_addrtuple **pat, |
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char *buffer, size_t buflen, int *errnop, |
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int *herrnop, int32_t *ttlp) |
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{ |
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+ enum nss_status status = check_name (name, herrnop); |
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+ if (status != NSS_STATUS_SUCCESS) |
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+ return status; |
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struct resolv_context *ctx = __resolv_context_get (); |
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if (ctx == NULL) |
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{ |
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@@ -346,7 +367,6 @@ _nss_dns_gethostbyname4_r (const char *name, struct gaih_addrtuple **pat, |
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int ans2p_malloced = 0; |
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int olderr = errno; |
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- enum nss_status status; |
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int n = __res_context_search (ctx, name, C_IN, T_QUERY_A_AND_AAAA, |
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host_buffer.buf->buf, 2048, &host_buffer.ptr, |
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&ans2p, &nans2p, &resplen2, &ans2p_malloced);
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